Zoom lens and imaging apparatus

ABSTRACT

Provided are a zoom lens which can be configured to have a small size while ensuring a high zoom ratio and has high optical performance by satisfactorily correcting chromatic aberration, and an imaging apparatus including the zoom lens. The zoom lens consists of, in order from the object side, a first lens group G1 that has a positive refractive power and remains stationary during zooming, a plurality of movable lens groups that move during zooming; and a final lens group Ge that has a positive refractive power and remains stationary during zooming. At least one movable lens group has a negative refractive power. The movable lens group, which is closest to the object side and has a negative refractive power, has two or more negative lenses, and satisfies predetermined conditional expressions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2016/081150 filed on Oct. 20, 2016, which claims priority under 35U.S.C. § 119(a) to Japanese Patent Application No. 2016-013137 filed onJan. 27, 2016. Each of the above application(s) is hereby expresslyincorporated by reference, in its entirety, into the presentapplication.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a zoom lens suitable for movie imagingcameras, broadcast cameras, digital cameras, video cameras, andsurveillance cameras, and to an imaging apparatus comprising the zoomlens.

2. Description of the Related Art

In the related art, a zoom lens having a four-group configuration or afive-group configuration has been proposed as a lens system that can beused for cameras in the above-mentioned fields. For example,JP2015-94866A describes a zoom lens having a four-group configurationand a zoom lens having a five-group configuration. The zoom lens havingthe four-group configuration is a lens system consisting of, in orderfrom the object side: a first lens group that has a positive refractivepower and remains stationary during zooming; a second lens group thathas a negative refractive power and moves during zooming; a third lensgroup that has a negative refractive power and moves during zooming; anda fourth lens group that has a positive refractive power and remainsstationary during zooming. The zoom lens having the five-groupconfiguration is a lens system consisting of, in order from the objectside: a first lens group that has a positive refractive power andremains stationary during zooming; a second lens group that has anegative refractive power and moves during zooming; a third lens groupthat has a negative refractive power and moves during zooming; a fourthlens group that has a negative refractive power and moves duringzooming; and a five lens group that has a positive refractive power andremains stationary during zooming. In addition, JP5777225B describes azoom lens having a four-group configuration. The zoom lens consists of,in order from the object side, a first lens group that has a positiverefractive power and remains stationary during zooming; a second lensgroup that has a negative refractive power and moves during zooming; athird lens group that has a negative refractive power and moves duringzooming; and a fourth lens group that has a positive refractive powerand remains stationary during zooming.

SUMMARY OF THE INVENTION

Meanwhile, in cameras in the above-mentioned field, it is desired that ahigher-resolution image can be acquired with a higher zoom ratio. Inorder to obtain a high-resolution image, it is necessary tosatisfactorily correct chromatic aberration of the lens system to bemounted. However, in a case where the configuration is intended to beapplied, the number of lenses tends to be large. This leads to anincrease in size of the lens system. There is a demand for a lens systemwhich can be configured to have a small size by minimizing the number oflenses and in which a high zoom ratio and high performance are achieved.

However, in the lens system described in JP2015-94866A, the number oflenses of the first lens group is large and reduction in size is notachieved, or the zoom ratio is insufficient. It is desired that the lenssystem described in JP5777225B has a higher zoom ratio in order to meetthe recent demands.

The present invention has been made in consideration of theabove-mentioned situations, and its object is to provide a zoom lenswhich can be configured to have a small size while ensuring a high zoomratio and has high optical performance by satisfactorily correctingchromatic aberration, and an imaging apparatus comprising the zoom lens.

A zoom lens of the present invention comprises, in order from an objectside: a first lens group that has a positive refractive power andremains stationary with respect to an image plane during zooming; aplurality of movable lens groups that move by changing distances betweengroups adjacent to each other in a direction of an optical axis duringzooming; and a final lens group that has a positive refractive power andremains stationary with respect to the image plane during zooming. Inthe plurality of movable lens groups, at least one movable lens grouphas a negative refractive power. In a case where the movable lens groupwhich is closest to the object side and has a negative refractive poweris set as a front side negative lens group, the front side negative lensgroup has two or more negative lenses. In addition, all ConditionalExpressions (1) to (3) are satisfied.

2.395<NF2+0.012×vF2<2.495   (1)

−35<vF1−vF2<−16   (2)

0.12<NF1−NF2<0.34   (3)

Here, NF2 is a refractive index of a second negative lens from theobject side in the front side negative lens group at the d line,

vF2 is an Abbe number of the second negative lens from the object sidein the front side negative lens group at the d line,

vF1 is an Abbe number of a negative lens closest to the object side inthe front side negative lens group at the d line, and

NF1 is a refractive index of the negative lens closest to the objectside in the front side negative lens group at the d line.

In the zoom lens of the present invention, it is preferable that atleast one of Conditional Expression (4), (1-1), (2-1), (3-1), or (4-1)is satisfied.

0.93<fF2/fGNF<1.1   (4)

2.395<NF2+0.012×vF2<2.455   (1-1)

−33<vF1−vF2<−18   (2-1)

0.13<NF1−NF2<0.31   (3-1)

0.94<fF2/fGNF<1.05   (4-1)

Here, fF2 is a focal length of the second negative lens from the objectside in the front side negative lens group,

fGNF is a focal length of the front side negative lens group,

NF2 is a refractive index of a second negative lens from the object sidein the front side negative lens group at the d line,

vF2 is an Abbe number of the second negative lens from the object sidein the front side negative lens group at the d line,

vF1 is an Abbe number of a negative lens closest to the object side inthe front side negative lens group at the d line, and

NF1 is a refractive index of the negative lens closest to the objectside in the front side negative lens group at the d line.

In the zoom lens of the present invention, in the plurality of movablelens groups, at least two movable lens groups all have a negativerefractive power. In a case where the movable lens group which isclosest to an image side and has a negative refractive power is set as arear side negative lens group, it is preferable that the rear sidenegative lens group includes a negative lens and a positive lens, andConditional Expressions (5) and (6) are satisfied. In this case, it ismore preferable that Conditional Expressions (5) and (6) are satisfiedand then Conditional Expressions (5-1) and/or (6-1) are satisfied.

2.395<NRn+0.012×vRn<2.495   (5)

25<vRn−vRp<35   (6)

2.395<NRn+0.012×vRn2<2.455   (5-1)

27<vRn−vRp<30   (6-1)

Here, NRn is a refractive index of the negative lens of the rear sidenegative lens group at the d line,

vRn is an Abbe number of the negative lens of the rear side negativelens group at the d line, and

vRp is an Abbe number of the positive lens of the rear side negativelens group at the d line.

In a case where the rear side negative lens group includes the negativelens and the positive lens, it is more preferable that ConditionalExpression (7) is satisfied, and it is more preferable that ConditionalExpression (7-1) is satisfied.

0.35<fRn/fGNR<0.51   (7)

0.37<fRn/fGNR<0.48   (7-1)

Here, fRn is a focal length of the negative lens of the rear sidenegative lens group, and

fGNR is a focal length of the rear side negative lens group.

In the zoom lens of the present invention, the plurality of movable lensgroups may be configured to include a lens group having a negativerefractive power and a lens group having a negative refractive power.Alternatively, the plurality of movable lens groups may be configured toinclude, in order from the object side, a lens group having a positiverefractive power, a lens group having a negative refractive power, and alens group having a negative refractive power. Alternatively, theplurality of movable lens groups may be configured to include, in orderfrom the object side, a lens group having a negative refractive power, alens group having a positive refractive power, and a lens group having anegative refractive power.

An imaging apparatus of the present invention comprises the zoom lens ofthe present invention.

In the present specification, it should be noted that the term“substantially consisting of ˜” and “substantially consists of ˜” meansthat the imaging lens may include not only the above-mentioned elementsbut also lenses substantially having no powers, optical elements, whichare not lenses, such as a stop, and/or a cover glass, and mechanismparts such as a lens flange, a lens barrel, and/or a camera shakingcorrection mechanism.

It should be noted that the “lens group” is not necessarily composed ofa plurality of lenses, but may be composed of only one lens. The above“˜ lens group having a positive refractive power” and “˜ lens grouphaving a negative refractive power” each represent the sign of therefractive power of the corresponding lens group as a whole. Signs ofrefractive powers of the lens groups and signs of refractive powers ofthe lenses are assumed as those in paraxial regions in a case where somelenses have aspheric surfaces. All the conditional expressions relate tothe d line (a wavelength of 587.6 nm, nm: nanometer) unless otherwisenoted.

It should be noted that the partial dispersion ratio θgF between the gline and the F line of a certain lens is defined by θgF=(Ng−NF)/(NF−NC),where Ng, NF, and NC are the refractive indices of the lens at the gline, the F line, and the C line.

According to the present invention, the zoom lens consists of, in orderfrom the object side, the first lens group that has a positiverefractive power and remains stationary during zooming, the plurality ofmovable lens groups that move during zooming, and the final lens groupthat has a positive refractive power and remains stationary duringzooming. In the zoom lens, one or more movable lens groups are set asnegative lens groups, and the configuration of the movable lens groupshaving a negative refractive powers is set, such that the predeterminedconditional expressions are satisfied. With such a configuration, it ispossible to provide a zoom lens, which can be configured to have a smallsize while ensuring a high zoom ratio and has high optical performanceby satisfactorily correcting chromatic aberration, and an imagingapparatus comprising the zoom lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a configuration of a zoomlens of Example 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating rays and the configurationof the zoom lens shown in FIG. 1, where the upper part thereof shows thezoom lens in the wide-angle end state, the middle part thereof shows thezoom lens in the middle focal length state, and the lower part thereofshows the zoom lens in the telephoto end state.

FIG. 3 is a cross-sectional view illustrating a configuration of a zoomlens of Example 2 of the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of a zoomlens of Example 3 of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a zoomlens of Example 4 of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a zoomlens of Example 5 of the present invention.

FIG. 7 is a cross-sectional view illustrating a configuration of a zoomlens of Example 6 of the present invention.

FIG. 8 is a cross-sectional view illustrating a configuration of a zoomlens of Example 7 of the present invention.

FIG. 9 is a cross-sectional view illustrating a configuration of a zoomlens of Example 8 of the present invention.

FIG. 10 is a cross-sectional view illustrating a configuration of a zoomlens of Example 9 of the present invention.

FIG. 11 is a diagram of aberrations of the zoom lens according toExample 1 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 12 is a diagram of aberrations of the zoom lens according toExample 2 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 13 is a diagram of aberrations of the zoom lens according toExample 3 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 14 is a diagram of aberrations of the zoom lens according toExample 4 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 15 is a diagram of aberrations of the zoom lens according toExample 5 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 16 is a diagram of aberrations of the zoom lens according toExample 6 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 17 is a diagram of aberrations of the zoom lens according toExample 7 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 18 is a diagram of aberrations of the zoom lens according toExample 8 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 19 is a diagram of aberrations of the zoom lens according toExample 9 of the present invention, where the upper part thereof showsthe zoom lens in the wide-angle end state, the middle part thereof showsthe zoom lens in the middle focal length state, the lower part thereofshows the zoom lens in the telephoto end state, and aberration diagramsof each state are spherical aberration diagram, astigmatism diagram,distortion diagram, and lateral chromatic aberration diagram in orderfrom the left side.

FIG. 20 is a schematic configuration diagram of an imaging apparatusaccording to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to drawings. FIG. 1 is a cross-sectional view illustrating alens configuration of a zoom lens at the wide-angle end according to anembodiment of the present invention. FIG. 2 shows the lensconfigurations of the zoom lens shown in FIG. 1 and rays of eachconfiguration. In FIG. 2, the wide-angle end state is shown in the upperpart indicated by “WIDE”, and rays are shown as on-axis rays wa and rayswith the maximum angle of view wb. Further, the middle focal lengthstate is shown in the middle part indicated by “MIDDLE”, and rays areshown as on-axis rays ma and rays with the maximum angle of view mb. Inaddition, the telephoto end state are shown in the lower part indicatedby “TELE”, and rays are shown as on-axis rays to and rays with themaximum angle of view tb. The examples shown in FIGS. 1 and 2 correspondto the zoom lens of Example 1 to be described later. FIGS. 1 and 2 eachshow a state where the object at infinity is in focus, where the leftside of the drawing is the object side and the right side of the drawingis the image side. Hereinafter, description will be given mainly withreference to FIG. 1.

In order to mount the zoom lens on an imaging apparatus, it ispreferable to provide various filters and/or a protective cover glassbased on specification of the imaging apparatus. Thus, FIG. 1 shows anexample where an optical member PP, in which those are considered and ofwhich the incident surface and the exit surface are parallel, isdisposed between the lens system and the image plane Sim. However, aposition of the optical member PP is not limited to that shown in FIG.1, and it is also possible to adopt a configuration in which the opticalmember PP is omitted.

The zoom lens of the present embodiment substantially consists of, inorder from the object side along the optical axis Z: a first lens groupG1 that remains stationary with respect to an image plane Sim duringzooming and has a positive refractive power; a plurality of movable lensgroups that move by changing distances between groups adjacent to eachother in a direction of an optical axis during zooming; and a final lensgroup Ge that has positive refractive power and remains stationary withrespect to the image plane Sim during zooming.

In the plurality of movable lens groups, at least one movable lens groupis configured to have a negative refractive power. Further, in theplurality of movable lens groups, it is preferable that at least twomovable lens groups all are configured to have a negative refractivepower. The zoom lens of the example shown in FIG. 1 is an example inwhich two movable lens groups have negative refractive powers.Hereinafter, among the plurality of movable lens groups arranged betweenthe first lens group G1 and the final lens group Ge, the movable lensgroup, which has a negative refractive power and is closest to theobject side, is referred to as a front side negative lens group GNF, andthe movable lens group, which has a negative refractive power and isclosest to the image side, is referred to as the rear side negative lensgroup GNR.

The zoom lens of the example shown in FIG. 1 substantially consists of,in order from the object side along the optical axis Z, a first lensgroup G1 having a positive refractive power, a second lens group G2having a negative refractive power, a third lens group G3 having anegative refractive power, and a fourth lens group G4 having a positiverefractive power. During zooming, the first lens group G1 and the fourthlens group G4 remain stationary with respect to the image plane Sim, andthe second lens group G2 and the third lens group G3 move by changing arelative distance therebetween in the direction of the optical axis. Inthe example shown in FIG. 1, the second lens group G2 and the third lensgroup G3 each are a movable lens group, the second lens group G2corresponds to the front side negative lens group GNF, the third lensgroup G3 corresponds to the rear side negative lens group GNR, and thefourth lens group G4 corresponds to the final lens group Ge. In FIG. 1,under each of the second lens group G2 and the third lens group G3, adirection of moving each lens group during zooming from the wide-angleend to the telephoto end is schematically indicated by an arrow.

In the example shown in FIG. 1, the first lens group G1 consists of atotal of eight lenses including a first negative lens L11, a secondnegative lens L12, and lenses L13 to L18 in order from the object side.The second lens group G2 consists of four lenses including lenses L21 toL24 in order from the object side. The third lens group G3 consists oftwo lenses including lenses L31 and L32 in order from the object side.The fourth lens group G4 consists of nine lenses including lenses L41 toL49 in order from the object side. However, in the zoom lens of thepresent invention, the number of lenses composing each lens group is notnecessarily limited to the example shown in FIG. 1.

FIG. 1 shows an example in which an aperture stop St is disposed betweenthe third lens group G3 and the fourth lens group G4, but the aperturestop St may be disposed at another position. Further, the aperture stopSt shown in FIG. 1 does not necessarily indicate its sizes and/orshapes, and indicates a position of the aperture stop St on the opticalaxis Z.

In the zoom lens of the present embodiment, by forming the first lensgroup G1 closest to the object side as a positive lens group, it ispossible to shorten the total length of the lens system, and thus thereis an advantage in reduction in size. By forming the final lens group Geclosest to the image side as the positive lens group, it is possible tosuppress an increase in incident angle of the principal ray of theoff-axis rays incident onto the image plane Sim. As a result, it ispossible to suppress shading. In addition, by adopting a configurationin which the lens group closest to the object side and the lens groupclosest to the image side remain stationary during zooming, it ispossible to make the total length of the lens system unchanged duringzooming.

In the plurality of movable lens group, at least one movable lens grouphas a negative refractive power. Thus, it is possible to contribute torealization of a high zoom ratio.

The front side negative lens group GNF is configured to have two or morenegative lenses and to satisfy Conditional Expressions (1) to (3).

2.395<NF2+0.012×vF2<2.495   (1)

−35<vF1−vF2<−16   (2)

0.12<NF1−NF2<0.34   (3)

Here, NF2 is a refractive index of a second negative lens from theobject side in the front side negative lens group at the d line,

vF2 is an Abbe number of the second negative lens from the object sidein the front side negative lens group at the d line,

vF1 is an Abbe number of a negative lens closest to the object side inthe front side negative lens group at the d line, and

NF1 is a refractive index of the negative lens closest to the objectside in the front side negative lens group at the d line.

By not allowing the result of Conditional Expression (1) to be equal toor less than the lower limit, it is possible to prevent the power of thelens necessary for achromatizing lateral chromatic aberration on thewide-angle side from becoming too strong. Thereby, it is possible tosuppress change in spherical aberration caused by zooming. By notallowing the result of Conditional Expression (1) to be equal to orgreater than the upper limit, it is possible to prevent the power of thelens necessary for lateral chromatic aberration on the wide-angle sidefrom becoming too weak, and it is possible to minimize an amount ofmovement of the movable lens group during zooming. Thus, it becomes easyto realize a high zoom ratio while achieving reduction in size. Further,it is preferable to satisfy Conditional Expression (1-1). By notallowing the result of Conditional Expression (1-1) to be equal to orgreater than the upper limit, it is possible to further increase aneffect relating to an upper limit of Conditional Expression (1).

2.395<NF2+0.012×vF2<2.455   (1-1)

By not allowing the result of Conditional Expression (2) to be equal toor less than the lower limit, it is possible to prevent lateralchromatic aberration on the wide-angle side from being insufficientlycorrected, and to prevent longitudinal chromatic aberration on thetelephoto side from being insufficiently corrected. As a result, thereis an advantage in obtaining favorable optical performance. By notallowing the result of Conditional Expression (2) to be equal to orgreater than the upper limit, it is possible to prevent lateralchromatic aberration on the wide-angle side from being excessivelycorrected, and to prevent longitudinal chromatic aberration on thetelephoto side from being excessively corrected. As a result, there isan advantage in obtaining favorable optical performance. In order tomore enhance the effect of Conditional Expression (2), it is preferablethat Conditional Expression (2-1) is satisfied.

−33<vF1−vF2<−18   (2-1)

By not allowing the result of Conditional Expression (3) to be equal toor less than the lower limit, it is possible to prevent sphericalaberration from increasing on the long focal length side. Thereby, itbecomes easy to realize a high zoom ratio. By not allowing the result ofConditional Expression (3) to be equal to or greater than the upperlimit, it is possible to reduce lateral chromatic aberration on thewide-angle side. Thereby, there is an advantage in obtaining favorableoptical performance. In order to more enhance the effect of ConditionalExpression (3), it is preferable that Conditional Expression (3-1) issatisfied.

0.13<NF1−NF2<0.31   (3-1)

By selecting a material of the negative lens of the movable lens groupthat has a negative refractive power and is closest to the first lensgroup G1 so as to satisfy Conditional Expressions (1) to (3), there isan advantage in correction of chromatic aberration. As a result, it ispossible to reduce correction of chromatic aberration of the first lensgroup G1. That is, it is possible to minimize the number of lenses whilesatisfactorily correcting chromatic aberration. As a result, it ispossible to achieve reduction in size. Further, in the lens systemdescribed in patent document 1, in order to correct lateral chromaticaberration on the wide-angle side, the length from the aperture stop tothe image plane becomes long, and the total length of the lens becomeslong. In contrast, the zoom lens of the present embodiment is configuredto satisfactorily correct lateral chromatic aberration on the wide-angleside. Thus, it is possible to minimize the length from the aperture stopSt to the image plane Sim.

It is preferable that the zoom lens satisfies Conditional Expression (4)for the front side negative lens group GNF.

0.93<fF2/fGNF<1.1   (4)

Here, fF2 is a focal length of the second negative lens from the objectside in the front side negative lens group, and

fGNF is a focal length of the front side negative lens group.

By not allowing the result of Conditional Expression (4) to be equal toor less than the lower limit, it is possible to prevent the power of thesecond negative lens from the object side in the front side negativelens group GNF from being excessively strong. As a result, it ispossible to reduce change in spherical aberration and/or astigmatismcaused by zooming. By not allowing the result of Conditional Expression(4) to be equal to or greater than the upper limit, it is possible toprevent the power of the second negative lens from the object side inthe front side negative lens group GNF. As a result, it becomes easy tocorrect lateral chromatic aberration on the wide-angle side. In order tomore enhance the effect of Conditional Expression (4), it is morepreferable that Conditional Expression (4-1) is satisfied.

0.94<fF2/fGNF<1.05   (4-1)

It is preferable that the rear side negative lens group GNRsubstantially consists of a negative lens and a positive lens. In such acase, it is possible to suppress change in longitudinal chromaticaberration caused by zooming. It should be noted that the rear sidenegative lens group GNR may be configured to consist of a negative lensand a positive lens in order from the object side, or may be configuredto consist of a positive lens and a negative lens in order from theobject side.

In a case where the rear side negative lens group GNR substantiallyconsist of a negative lens and a positive lens, it is preferable tosatisfy Conditional Expressions (5) and (6).

2.395<NRn+0.012×vRn<2.495   (5)

25<vRn−vRp<35   (6)

Here, NRn is a refractive index of the negative lens of the rear sidenegative lens group at the d line,

vRn is an Abbe number of the negative lens of the rear side negativelens group at the d line, and

vRp is an Abbe number of the positive lens of the rear side negativelens group at the d line.

By not allowing the result of Conditional Expression (5) to be equal toor less than the lower limit, it is possible to prevent the power of thelens necessary for achromatizing longitudinal chromatic aberration onthe wide-angle side from becoming too strong. Thereby, it is possible tosuppress change in spherical aberration caused by zooming. By notallowing the result of Conditional Expression (5) to be equal to orgreater than the upper limit, it is possible to prevent the power of thelens necessary for longitudinal chromatic aberration on the wide-angleside from becoming too weak, and it is possible to minimize an amount ofmovement of the movable lens group during zooming. Thus, it becomes easyto realize a high zoom ratio while achieving reduction in size. Further,it is preferable to satisfy Conditional Expression (5-1). By notallowing the result of Conditional Expression (5-1) to be equal to orgreater than the upper limit, it is possible to further increase aneffect relating to an upper limit of Conditional Expression (5).

2.395<NRn+0.012×vRn2<2.455   (5-1)

By not allowing the result of Conditional Expression (6) to be equal toor less than the lower limit, it is possible to prevent longitudinalchromatic aberration on the wide-angle side from being insufficientlycorrected. Thereby, there is an advantage in obtaining favorable opticalperformance. By not allowing the result of Conditional Expression (6) tobe equal to or greater than the upper limit, it is possible to preventlongitudinal chromatic aberration on the wide-angle side from beingexcessively corrected. Thereby, there is an advantage in obtainingfavorable optical performance. In order to more enhance the effect ofConditional Expression (6), it is more preferable that ConditionalExpression (6-1) is satisfied.

27<vRn−vRp<30   (6-1)

In a case where the rear side negative lens group GNR substantiallyconsists of a negative lens and a positive lens, it is preferable tosatisfy Conditional Expression (7).

0.35<fRn/fGNR<0.51   (7)

Here, fRn is a focal length of the negative lens of the rear sidenegative lens group, and

fGNR is a focal length of the rear side negative lens group.

By not allowing the result of Conditional Expression (7) to be equal toor less than the lower limit, it is possible to prevent the power of thenegative lens in the rear side negative lens group GNR from beingexcessively strong. As a result, it is possible to reduce change inspherical aberration and/or astigmatism caused by zooming. By notallowing the result of Conditional Expression (7) to be equal to orgreater than the upper limit, it is possible to prevent the power of thenegative lens in the rear side negative lens group GNR from beingexcessively weak. As a result, it is possible to prevent longitudinalchromatic aberration from being insufficiently corrected. In order tomore enhance the effect of Conditional Expression (7), it is morepreferable that Conditional Expression (7-1) is satisfied.

0.37<fRn/fGNR<0.48   (7-1)

In addition, in the example shown in FIG. 1, the number of pluralmovable lens groups arranged between the first lens group G1 and thefinal lens group Ge is two, and these two movable lens groups also havenegative refractive powers. In such a case, it is possible to realize azoom lens having a small size and a high zoom ratio while simplifyingthe mechanism.

However, the number of plural movable lens groups arranged between thefirst lens group G1 and the final lens group Ge may be configured to bethree or more. For example, the plurality of movable lens groups may beconfigured to substantially consist of, in order from the object side, alens group having a positive refractive power, a lens group having anegative refractive power, and a lens group having a negative refractivepower. In such a case, it is possible to realize a zoom lens having asmall size and a high zoom ratio while suppressing occurrence ofdistortion on the wide-angle side and/or spherical aberration on thetelephoto side. Alternatively, the plurality of movable lens groups maybe configured to substantially consist of, in order from the objectside, a lens group having a negative refractive power, a lens grouphaving a positive refractive power, and a lens group having a negativerefractive power. In such a case, aberrations are easily corrected, anda zoom lens having a small size and a high zoom ratio can be realized.

Further, in the plurality of movable lens groups, it is preferable thata movable lens group closest to the image side has a negative refractivepower. In such a case, the movement stroke of the movable lens grouplocated closer to the object side than the movable lens group closest tothe image side can be set to be longer while minimizing the total lengthof the lens system. Thus, there is an advantage in achieving reductionin size and high zoom ratio.

In addition, the zoom lens may be configured to perform focusing whenthe distance to the object changes, by moving one or more lenses in thefirst lens group G1 in the direction of the optical axis. As describedabove, focusing is performed by using a lens closer to the object sidethan a lens group moving during zooming, and thus it becomes easy tosuppress the shift of focus during zooming.

For example, the first lens group G1 of the example shown in FIG. 1substantially consists of, in order from the object side, a first lensgroup front group G1 a that has a negative refractive power and remainsstationary with respect to the image plane Sim during focusing, a firstlens group intermediate group G1 b that has a positive refractive powerand moves in the direction of the optical axis during focusing, and afirst lens group rear group G1 c that is set such that a distance in thedirection of the optical axis between the first lens group rear group G1c and the first lens group intermediate group G1 b changes duringfocusing and has a positive refractive power. In a case of adopting sucha configuration, it becomes easy to suppress change in the angle of viewcaused by focusing. In FIG. 1, both arrows below the first lens groupintermediate group G1 b indicate that the first lens group intermediategroup G1 b is movable in the directions of the optical axis duringfocusing.

In addition, the first lens group rear group G1 c may remain stationarywith respect to the image plane Sim during focusing. In such a case, thelens groups, which move during focusing, can be composed of a number ofonly the first lens group intermediate group G1 b, and it is possible tosimplify the focusing mechanism. Thus, it is possible to suppress anincrease in size of the apparatus. Alternatively, the first lens grouprear group G1 c may move in the direction of the optical axis along alocus different from that of the first lens group intermediate group G1b during focusing. In such a case, it is possible to suppressfluctuation in aberration during focusing.

The first lens group front group G1 a may be configured to have,successively in order from a position closest to the object side, anegative meniscus lens concave toward an image side, and a negative lensconcave toward the object side. In such a case, it is possible to obtaina negative refractive power necessary for achieving wide angle whilesuppressing occurrence of astigmatism. The lens closest to the imageside in the first lens group front group G1 a may be a positive meniscuslens concave toward the image side. In such a case, it is possible tosuppress occurrence of astigmatism on the wide-angle side. Further, itis also possible to satisfactorily correct spherical aberration, whichis generated by the first lens group front group G1 a and has an overtendency on the telephoto side, particularly spherical aberration havinga high order which is 5th order or more. As in the example of FIG. 1,the first lens group front group G1 a consists of, in order from theobject side, a negative meniscus lens, a negative lens, and a positivemeniscus lens. These three lenses may be single lenses which are notentirely cemented. In such a case, it is possible to obtain a negativerefractive power necessary for achieving wide angle while achievingreduction in size and suppressing occurrence of astigmatism.

It is preferable that the first lens group rear group G1 c has,successively in order from the object side, a cemented lens, in which anegative lens and a positive lens are cemented in order from the objectside, and a positive lens. In such a case, it becomes easy to correctchromatic aberration of the first lens group G1 and correct sphericalaberration on the telephoto side. In addition, in the case where thefirst lens group rear group G1 c is configured to consist of, in orderfrom the object side, a cemented lens, in which a negative lens and apositive lens are cemented in order from the object side, and a positivelens, it is possible to easily correct chromatic aberration of the firstlens group G1 and correct spherical aberration on the telephoto sidewhile achieving reduction in size.

The above-mentioned preferred configurations and/or availableconfigurations each may be any combination, and it is preferable toappropriately selectively adopt the configuration in accordance withdemands for the zoom lens. By appropriately adopting the configuration,it is possible to realize more favorable optical system. According tothe present embodiment, it is possible to realize a zoom lens, which hasa small size while ensuring a high zoom ratio and has high opticalperformance in the entire zooming range by satisfactorily correctingchromatic aberration. It should be noted that the high zoom ratiodescribed herein means 5.5 times or more.

Next, numerical examples of the zoom lens of the present invention willbe described.

Example 1

A lens configuration of a zoom lens of Example 1 is shown in FIGS. 1 and2, and an illustration method thereof is as described above. Therefore,repeated description is partially omitted herein. The zoom lens ofExample 1 consists of, in order from the object side, a first lens groupG1, a second lens group G2, a third lens group G3, an aperture stop St,and a fourth lens group G4. In these four lens groups, the distances inthe direction of the optical axis between groups adjacent to each otherchange during zooming. Both the second lens group G2 and the third lensgroup G3 are movable lens groups having negative refractive powers. Thefirst lens group G1 consists of, in order from the object side, a firstlens group front group G1 a that consists of three lenses and has anegative refractive power, a first lens group intermediate group G1 bthat consists of two lenses and has a positive refractive power, and afirst lens group rear group G1 c that consists of three lenses and has apositive refractive power. During focusing, the first lens group frontgroup G1 a remains stationary with respect to the image plane Sim, thefirst lens group intermediate group G1 b moves, and the distance in thedirection of the optical axis between the first lens group intermediategroup G1 b and the first lens group rear group G1 c changes.

Table 1 shows basic lens data of the zoom lens of Example 1, Table 2shows values of specification and variable surface distances, and Table3 shows aspheric coefficients thereof. In Table 1, the column of Sishows a surface number i (i=1, 2, 3, . . . ) attached to an i-th surfaceof the elements, where i sequentially increases toward the image side ina case where an object side surface of an element closest to the objectside is regarded as a first surface. The column of Ri shows a radius ofcurvature of the i-th surface. The column of Di shows a distance on theoptical axis Z between the i-th surface and an (i+1)th surface. In Table1, the column of Ndj shows a refractive index of a j-th (j=1, 2, 3, . .. ) element at the d line (a wavelength of 587.6 nm), where jsequentially increases toward the image side in a case where the elementclosest to the object side is regarded as the first element. The columnof vdj shows an Abbe number of the j-th element at the d line. Thecolumn of θgFj shows a partial dispersion ratio of the j-th elementbetween the g line and the F line.

Here, reference signs of radii of curvature of surface shapes convextoward the object side are set to be positive, and reference signs ofradii of curvature of surface shapes convex toward the image side areset to be negative. Table 1 additionally shows the aperture stop St andthe optical member PP. In Table 1, in a place of a surface number of asurface corresponding to the aperture stop St, the surface number and aterm of (St) are noted. A value at the bottom place of Di indicates adistance between the image plane Sim and the surface closest to theimage side in the table. In Table 1, the variable surface distances,which are variable during zooming, are referenced by the reference signsDD[ ], and are written into places of Di, where object side surfacenumbers of distances are noted in [ ].

In Table 2, values of the zoom ratio Zr, the focal length f of the wholesystem, the back focal length Bf in terms of the air conversiondistance, the F number FNo., the maximum total angle of view 2ω, andvariable surface distance are based on the d line. (°) in the place of2w indicates that the unit thereof is a degree. In Table 2, values inthe wide-angle end state, the middle focal length state, and thetelephoto end state are respectively shown in the columns labeled byWIDE, MIDDLE, and TELE. The values of Tables 1 and 2 are values in astate where the object at infinity is in focus.

In Table 1, the reference sign * is attached to surface numbers ofaspheric surfaces, and numerical values of the paraxial radius ofcurvature are written into the column of the radius of curvature of theaspheric surface. Table 3 shows aspheric coefficients of the asphericsurfaces of Example 1. The “E-n” (n: an integer) in numerical values ofthe aspheric coefficients of Table 3 indicates “×10^(-n)”. The asphericcoefficients are values of the coefficients KA and Am (m=3, 4, 5, . . ., 20) in aspheric surface expression represented as the followingexpression.

$\begin{matrix}{{Zd} = {\frac{C \times h^{2}}{1 + \sqrt{1 - {{KA} \times C^{2} \times h^{2}}}} + {\underset{m}{\Sigma}{Am} \times h^{m}}}} & {{Numerical}\mspace{14mu} {Expression}\mspace{14mu} 1}\end{matrix}$

Here, Zd is an aspheric surface depth (a length of a perpendicular froma point on an aspheric surface at height h to a plane that isperpendicular to the optical axis that contacts with the vertex of theaspheric surface),

h is a height (a length of a perpendicular, which is in a planeperpendicular to the optical axis that contacts with the vertex of theaspheric surface, from the point on the aspheric surface to the opticalaxis),

C is a paraxial curvature, and

KA and Am are aspheric coefficients.

In data of each table, a degree is used as a unit of an angle, andmillimeter (mm) is used as a unit of a length, but appropriate differentunits may be used since the optical system can be used even in a casewhere the system is enlarged or reduced in proportion. Further, each ofthe following tables shows numerical values rounded off to predetermineddecimal places.

TABLE 1 Example 1 Si Ri Di Ndj vdj θgFj  1 370.38276 2.53000 1.77249949.60 0.5521  2 57.75739 26.80621   3 −152.87368 2.20000 1.695602 59.050.5435  4 486.73340 0.39000  5 103.42182 4.56107 1.892860 20.36 0.6394 6 194.06007 6.98917  7 ∞ 6.83489 1.438750 94.66 0.5340  8 −128.102020.12000  9 371.48362 5.66802 1.438750 94.66 0.5340  10 −249.304749.12857  11 93.94676 2.19983 1.846660 23.88 0.6218  12 56.3955816.02634  1.438750 94.66 0.5340  13 −130.65476 0.12000  14 72.969835.84576 1.695602 59.05 0.5435  15 264.75541 DD[15] *16 47.39581 1.380001.854000 40.38 0.5689  17 23.64140 7.04442  18 −51.14856 1.049101.632460 63.77 0.5421  19 38.48116 5.84592  20 44.54062 5.58518 1.59270135.31 0.5934  21 −55.99669 1.05000 1.592824 68.62 0.5441  22 −270.02836DD ]22]  23 −39.56418 1.05000 1.632460 63.77 0.5421  24 44.13413 4.046161.625882 35.70 0.5893  25 −177.97071 DD[25]  26(St) ∞ 1.52068  27134.91398 3.33963 1.916500 31.60 0.5912  28 −85.19407 0.20018  2930.90160 8.07631 1.496999 81.54 0.5375  30 −41.69367 1.89903 1.91082335.25 0.5822  31 85.64653 5.33750  32 36.30103 6.58324 1.749497 35.280.5870  33 −105.50860 0.99910  34 138.71124 1.10000 1.900433 37.370.5772  35 18.11707 9.50941 1.632460 63.77 0.5421  36 −111.49284 0.11910 37 39.11125 8.33426 1.438750 94.66 0.5340  38 −24.02071 2.000901.953748 32.32 0.5901  39 27.28562 18.99884   40 48.65552 4.694581.720467 34.71 0.5835  41 −182.07198 0.00000  42 ∞ 2.30000 1.51633064.14 0.5353  43 ∞ 34.04250 

TABLE 2 Example 1 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.45 59.31118.42 Bf 35.56 35.56 35.56 FNo. 3.32 3.32 3.32 2ω(°) 72.32 26.30 13.50DD[15] 1.54 42.02 57.17 DD[22] 47.88 7.36 5.49 DD[25] 14.71 14.75 1.47

TABLE 3 Example 1 Surface Number 16 KA   1.0000000E+00 A3 −1.4481371E−20A4 −2.2097151E−06 A5   1.1906712E−06 A6 −2.1344004E−07 A7  1.2774506E−08 A8   1.1294113E−09 A9 −2.3286340E−10 A10   1.4115083E−11A11   4.6903088E−13 A12 −1.7545649E−13 A13   9.6716937E−15 A14  6.5945061E−16 A15 −7.7270143E−17 A16 −2.4667346E−19 A17  2.3248734E−19 A18 −4.1986679E−21 A19 −2.5896844E−22 A20  7.5912487E−24

FIG. 11 shows aberration diagrams in a state where an object at infinityis brought into focus through the zoom lens of Example 1. In order fromthe left side of FIG. 11, spherical aberration, astigmatism, distortion,and lateral chromatic aberration (lateral chromatic aberration) areshown. In FIG. 11, the upper part labeled by WIDE shows the zoom lens inthe wide-angle end state, the middle part labeled by MIDDLE shows thezoom lens in the middle focal length state, the lower part labeled byTELE shows the zoom lens in the telephoto end state. In the sphericalaberration diagram, aberrations at the d line (a wavelength of 587.6nm), the C line (a wavelength of 656.3 nm), the F line (a wavelength of486.1 nm), and the g line (a wavelength of 435.8 nm) are respectivelyindicated by the black solid line, the long dashed line, the chain line,and the gray solid line. In the astigmatism diagram, aberration in thesagittal direction at the d line is indicated by the solid line, andaberration in the tangential direction at the d line is indicated by theshort dashed line. In the distortion diagram, aberration at the d lineis indicated by the solid line. In the lateral chromatic aberrationdiagram, aberrations at the C line, the F line, and the g line arerespectively indicated by the long dashed line, the chain line, and thegray solid line. In the spherical aberration diagram, FNo. indicates anF number. In the other aberration diagrams, co indicates a half angle ofview.

In the description of Example 1, reference signs, meanings, anddescription methods of the respective data pieces are the same as thosein the following examples unless otherwise noted. Therefore, in thefollowing description, repeated description will be omitted.

Example 2

FIG. 3 is a cross-sectional view of a zoom lens of Example 2. The zoomlens of Example 2 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, anaperture stop St, and a fourth lens group G4. The first lens group G1consists of, in order from the object side, a first lens group frontgroup G1 a consisting of three lenses, a first lens group intermediategroup G1 b consisting of two lenses, and a first lens group rear groupG1 c consisting of three lenses. The present example is the same asExample 1 in terms of the signs of refractive powers of the lens groups,the lens groups moving during zooming, and the lens groups moving duringfocusing.

Table 4 shows basic lens data of the zoom lens of Example 2, Table 5shows values of specification and variable surface distances, Table 6shows aspheric coefficients, and FIG. 12 shows aberration diagrams in astate where the object at infinity is in focus.

TABLE 4 Example 2 Si Ri Di Ndj vdj θgFj  1 91.92719 2.53098 1.77249949.60 0.5521  2 47.04979 22.24446   3 −170.66128 2.20000 1.632460 63.770.5421  4 206.04456 0.38503  5 71.99393 4.45167 1.892860 20.36 0.6394  6102.54612 6.82807  7 196.27328 2.20005 1.772499 49.60 0.5521  8103.84467 11.12110  1.438750 94.66 0.5340  9 −171.05234 14.89014   1096.08666 2.19923 1.854780 24.80 0.6123  11 58.74401 15.93330  1.43875094.66 0.5340  12 −103.69633 0.12000  13 75.26293 6.27475 1.695602 59.050.5435  14 827.30524 DD[14] *15 72.65286 1.38000 1.854000 40.38 0.5689 16 25.93821 6.72575  17 −41.69691 1.05070 1.592824 68.62 0.5441  1837.57713 4.48600  19 44.63168 5.32952 1.592701 35.31 0.5934  20−52.52729 1.05090 1.592824 68.62 0.5441  21 −121.55768 DD[21]  22−42.05800 1.04975 1.632460 63.77 0.5421  23 39.59542 4.12871 1.62588235.70 0.5893  24 −246.96103 DD[24]  25(St) ∞ 1.39983  26 140.447903.12682 1.916500 31.60 0.5912  27 −89.38492 0.20011  28 28.98877 8.219541.496999 81.54 0.5375  29 −42.61188 1.10000 1.910823 35.25 0.5822  3090.28815 5.81177  31 39.25421 6.59993 1.749497 35.28 0.5870  32−89.09971 1.37631  33 139.77728 1.13913 1.900433 37.37 0.5772  3417.41563 9.99924 1.695602 59.05 0.5435  35 −724.38203 0.12001  3629.98468 6.67820 1.438750 94.66 0.5340  37 −24.61428 2.00000 1.95374832.32 0.5901  38 25.83563 20.39478   39 47.76648 5.13049 1.720467 34.710.5835  40 −176.41808 0.00000  41 ∞ 2.30000 1.516330 64.14 0.5353  42 ∞34.52368 

TABLE 5 Example 2 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.62 59.81119.41 Bf 36.04 36.04 36.04 FNo. 3.31 3.31 3.30 2ω(°) 71.86 26.08 13.40DD[14] 1.00 41.46 56.83 DD[21] 49.91 8.08 4.34 DD[24] 12.04 13.41 1.78

TABLE 6 Example 2 Surface Number 15 KA   1.0000000E+00 A3  0.0000000E+00 A4 −7.0268357E−07 A5 −2.8254006E−07 A6   1.9442811E−07A7 −1.0869783E−08 A8 −6.5332158E−09 A9   1.0648429E−09 A10  8.0520025E−12 A11 −1.2814263E−11 A12   6.6704958E−13 A13  5.0970812E−14 A14 −5.3557213E−15 A15 −3.0887770E−18 A16  1.5245419E−17 A17 −4.1575720E−19 A18 −1.2158029E−20 A19  6.9438881E−22 A20 −8.1994339E−24

Example 3

FIG. 4 is a cross-sectional view of a zoom lens of Example 3. The zoomlens of Example 3 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, anaperture stop St, and a fourth lens group G4. The first lens group G1consists of, in order from the object side, a first lens group frontgroup G1 a consisting of three lenses, a first lens group intermediategroup G1 b consisting of two lenses, and a first lens group rear groupG1 c consisting of three lenses. The present example is the same asExample 1 in terms of the signs of refractive powers of the lens groups,the lens groups moving during zooming, and the lens groups moving duringfocusing.

Table 7 shows basic lens data of the zoom lens of Example 3, Table 8shows values of specification and variable surface distances, Table 9shows aspheric coefficients, and FIG. 13 shows aberration diagrams in astate where the object at infinity is in focus.

TABLE 7 Example 3 Si Ri Di Ndj vdj θgFj  1 179.73060 2.80000 1.88299740.76 0.5668  2 57.51902 19.98932   3 −182.56446 2.20000 1.632460 63.770.5421  4 156.29712 1.00000  5 89.75457 4.58961 1.922860 18.90 0.6496  6161.94294 6.83969  7 227.04433 2.20000 1.693717 42.53 0.5721  8104.53646 13.56898  1.438750 94.66 0.5340  9 −104.79903 8.44249  1088.91022 2.20000 1.805181 25.42 0.6162  11 56.35834 14.33676  1.43875094.66 0.5340  12 −212.00944 0.57436  13 90.10716 6.95580 1.695602 59.050.5435  14 −750.39403 DD[14] *15 59.64397 1.20000 1.902700 31.00 0.5943 16 28.07287 6.22761  17 −55.23848 1.20000 1.632460 63.77 0.5421  1839.20503 5.53307  19 46.62148 6.58080 1.592701 35.31 0.5934  20−34.36365 1.20000 1.592824 68.62 0.5441  21 −260.67806 DD[21]  22−44.46367 1.20000 1.632460 63.77 0.5421  23 64.72532 2.94300 1.62588235.70 0.5893  24 −221.99664 DD[24]  25(St) ∞ 1.60000  26 225.293532.92131 1.916500 31.60 0.5912  27 −75.69537 0.12000  28 33.19063 7.431921.496999 81.54 0.5375  29 −42.89577 1.50000 1.918781 36.12 0.5784  30127.40865 6.99461  31 40.56322 7.82296 1.749497 35.28 0.5870  32−113.63622 1.00008  33 166.07425 1.50000 1.900433 37.37 0.5772  3418.91770 6.77468 1.695602 59.05 0.5435  35 −143.93112 1.23445  3638.97329 8.62046 1.438750 94.66 0.5340  37 −28.03994 2.00000 1.95374832.32 0.5901  38 24.50898 22.08922   39 43.14369 5.29015 1.628270 44.120.5704  40 −162.61439 0.00000  41 ∞ 2.30000 1.516330 64.14 0.5353  42 ∞31.88502 

TABLE 8 Example 3 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.71 60.06119.92 Bf 33.40 33.40 33.40 FNo. 3.30 3.31 3.30 2ω(°) 71.42 25.92 13.34DD[14] 1.05 45.79 62.89 DD[21] 54.63 8.29 4.17 DD[24] 13.18 14.78 1.80

TABLE 9 Example 3 Surface Number 15 KA   1.0000000E+00 A4 −5.4302541E−07A6   2.3244121E−08 A8 −4.3760338E−10 A10   4.9556187E−12 A12−3.5362900E−14 A14   1.5550030E−16 A16 −3.9877943E−19 A18  5.2706205E−22 A20 −2.5738294E−25

Example 4

FIG. 5 is a cross-sectional view of a zoom lens of Example 4. The zoomlens of Example 4 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, anaperture stop St, and a fourth lens group G4. The first lens group G1consists of, in order from the object side, a first lens group frontgroup G1 a consisting of three lenses, a first lens group intermediategroup G1 b consisting of one lens, and a first lens group rear group G1c consisting of three lenses. The present example is the same as Example1 in terms of the signs of refractive powers of the lens groups, thelens groups moving during zooming, and the lens groups moving duringfocusing.

Table 10 shows basic lens data of the zoom lens of Example 4, Table 11shows values of specification and variable surface distances, Table 12shows aspheric coefficients, and FIG. 14 shows aberration diagrams in astate where the object at infinity is in focus.

TABLE 10 Example 4 Si Ri Di Ndj vdj θgFj  1 89.55061  2.53098 1.77249949.60 0.5521  2 46.20108 26.48567  3 −170.63384  2.20059 1.695602 59.050.5435  4 232.43449  0.39804  5 72.57068  4.47015 1.892860 20.36 0.6394 6 106.19898  9.28374  7 2685.83228  5.32667 1.438750 94.66 0.5340  8−153.59919 14.66212  9 113.63731  2.16853 1.854780 24.80 0.6123  1059.63066 15.98231 1.438750 94.66 0.5340  11 −90.12780  0.14311  1270.15326  7.22393 1.695602 59.05 0.5435  13 661.14022 DD[13] *1452.60017  1.38000 1.854000 40.38 0.5689  15 24.43846  7.35169  16−41.94664  1.05070 1.592824 68.62 0.5441  17 37.98271  4.32904  1843.08412  5.54251 1.592701 35.31 0.5934  19 −50.53315  1.05090 1.59282468.62 0.5441  20 −188.16409 DD[20]  21 −40.22044  1.05085 1.632460 63.770.5421  22 45.33398  3.77263 1.625882 35.70 0.5893  23 −236.50416 DD[23] 24(St) ∞  1.40031  25 167.28051  3.05237 1.916500 31.60 0.5912  26−82.28668  0.20010  27 29.42802  8.35992 1.496999 81.54 0.5375  28−39.92973  1.11193 1.910823 35.25 0.5822  29 109.93898  5.82991  3040.35878  6.58497 1.749497 35.28 0.5870  31 −84.78434  1.14152  32135.35453  1.80010 1.900433 37.37 0.5772  33 17.94607  9.53921 1.69560259.05 0.5435  34 −613.17875  0.38246  35 30.56287  6.55776 1.43875094.66 0.5340  36 −23.83965  1.99868 1.953748 32.32 0.5901  37 25.9480519.72576  38 46.63103  4.99544 1.720467 34.71 0.5835  39 −193.04666 0.00000  40 ∞  2.30000 1.516330 64.14 0.5353  41 ∞ 33.97254

TABLE 11 Example 4 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.40 59.15118.09 Bf 35.49 35.49 35.49 FNo. 3.31 3.31 3.30 2ω(°) 72.42 26.38 13.56DD[13] 0.41 41.66 57.48 DD[20] 51.15 8.62 3.96 DD[23] 10.75 12.04 0.88

TABLE 12 Example 4 Surface Number 14 KA   1.0000000E+00 A3  0.0000000E+00 A4 −7.0268357E−07 A5 −2.8254006E−07 A6   1.9442811E−07A7 −1.0869783E−08 A8 −6.5332158E−09 A9   1.0648429E−09 A10  8.0520025E−12 A11 −1.2814263E−11 A12   6.6704958E−13 A13  5.0970812E−14 A14 −5.3557213E−15 A15 −3.0887770E−18 A16  1.5245419E−17 A17 −4.1575720E−19 A18 −1.2158029E−20 A19  6.9438881E−22 A20 −8.1994339E−24

Example 5

FIG. 6 is a cross-sectional view of a zoom lens of Example 5. The zoomlens of Example 5 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, a fourthlens group G4, an aperture stop St, and a fifth lens group G5. In thesefive lens groups, the distances in the direction of the optical axisbetween groups adjacent to each other change during zooming. The secondlens group G2 has a positive refractive power, the third lens group G3has a negative refractive power, and the fourth lens group G4 has anegative refractive power. The three lens groups including the second tofourth lens groups G2 to G4 are respectively movable lens groups. Thefirst lens group G1 consists of, in order from the object side, a firstlens group front group G1 a consisting of three lenses, a first lensgroup intermediate group G1 b consisting of two lenses, and a first lensgroup rear group G1 c consisting of three lenses. The signs of therefractive powers of three lens groups composing the first lens group G1and the lens groups moving during focusing are the same as that ofExample 1.

Table 13 shows basic lens data of the zoom lens of Example 5, Table 14shows values of specification and variable surface distances, and FIG.15 shows aberration diagrams in a state where the infinite object is infocus.

TABLE 13 Example 5 Si Ri Di Ndj vdj θgFj  1 351.51134  2.53000 1.77249949.60 0.5521  2 58.96679 25.71058  3 −165.96934  2.60041 1.695602 59.050.5435  4 438.51863  0.38517  5 96.24927  3.97797 1.892860 20.36 0.6394 6 152.74199  7.45066  7 ∞  7.63521 1.438750 94.66 0.5340  8 −131.92076 0.12000  9 409.13255  5.76407 1.438750 94.66 0.5340 10 −220.57814 7.99290 11 108.72751  2.20000 1.755199 27.51 0.6103 12 55.8338614.41684 1.438750 94.66 0.5340 13 −168.55158  0.12000 14 73.70666 6.42934 1.632460 63.77 0.5421 15 597.12639 DD[15] 16 137.71857  2.631391.496999 81.54 0.5375 17 −1305.73558 DD[17] 18 87.40326  1.380001.834807 42.72 0.5649 19 30.33959  6.29623 20 −51.31471  1.050001.695602 59.05 0.5435 21 48.76135  8.19661 22 68.58699  3.87635 1.69894730.13 0.6030 23 −74.53716  1.06000 1.695602 59.05 0.5435 24 −291.58007DD[24] 25 −41.67152  1.05055 1.632460 63.77 0.5421 26 53.61308  3.934851.625882 35.70 0.5893 27 −158.08561 DD[27] 28(St) ∞  1.72135 29112.40514  3.36815 1.916500 31.60 0.5912 30 −107.74797  0.20079 3132.65637  7.66863 1.496999 81.54 0.5375 32 −44.13940  1.10000 1.91082335.25 0.5822 33 146.04040 11.71151 34 88.13789  3.58259 1.749497 35.280.5870 35 −61.95479  0.99901 36 81.54848  1.10000 1.900433 37.37 0.577237 20.55629  4.91890 1.632460 63.77 0.5421 38 122.56273  0.12011 3927.72661  9.31235 1.438750 94.66 0.5340 40 −30.83758  1.99952 1.95374832.32 0.5901 41 28.75987 20.68485 42 49.85885  4.26967 1.720467 34.710.5835 43 −342.76867  0.00000 44 ∞  2.30000 1.516330 64.14 0.5353 45 ∞33.79607

TABLE 14 Example 5 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.84 60.43120.65 Bf 35.31 35.31 35.31 FNo. 3.31 3.31 3.31 2ω(°) 71.32 25.74 13.20DD[15] 0.15 24.27 35.03 DD[17] 1.00 14.99 18.97 DD[24] 37.14 3.28 8.30DD[27] 25.73 21.48 1.71

Example 6

FIG. 7 is a cross-sectional view of a zoom lens of Example 6. The zoomlens of Example 6 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, a fourthlens group G4, an aperture stop St, and a fifth lens group G5. The firstlens group G1 consists of, in order from the object side, a first lensgroup front group G1 a consisting of three lenses, a first lens groupintermediate group G1 b consisting of two lenses, and a first lens grouprear group G1 c consisting of three lenses. The present example is thesame as Example 5 in terms of the signs of refractive powers of the lensgroups, the lens groups moving during zooming, and the lens groupsmoving during focusing.

Table 15 shows basic lens data of the zoom lens of Example 6, Table 16shows values of specification and variable surface distances, and FIG.16 shows aberration diagrams in a state where the infinite object is infocus.

TABLE 15 Example 6 Si Ri Di Ndj vdj θgFj  1 141.52029  2.53000 1.77249949.60 0.5521  2 52.25093 21.72306  3 −169.76115  2.60000 1.695602 59.050.5435  4 227.38169  0.38500  5 82.77517  4.42635 1.892860 20.36 0.6394 6 124.35002  8.58347  7 327.66786  2.00000 1.755199 27.51 0.6103  8118.32799 14.02000 1.496999 81.54 0.5375  9 −110.23986  9.77811 10106.66417  2.22000 1.592701 35.31 0.5934 11 53.48612 16.28831 1.43875094.66 0.5340 12 −149.79662  0.12001 13 82.59842  6.25291 1.695602 59.050.5435 14 756.00928 DD[14] 15 336.83164  2.18103 1.496999 81.54 0.537516 −474.99451 DD[16] 17 92.73731  1.38000 1.882997 40.76 0.5668 1831.26761  6.12521 19 −41.83728  1.05000 1.695602 59.05 0.5435 2050.59877  4.82631 21 62.85436  4.13921 1.698947 30.13 0.6030 22−71.03230  1.06003 1.695602 59.05 0.5435 23 −133.54667 DD[23] 24−39.50225  1.04910 1.632460 63.77 0.5421 25 33.98929  4.61700 1.62588235.70 0.5893 26 −303.50782 DD[26] 27(St) ∞  1.40000 28 81.21019  3.548131.916500 31.60 0.5912 29 −126.01058  0.19910 30 30.62497  8.168311.496999 81.54 0.5375 31 −38.67212  1.10094 1.910823 35.25 0.5822 32149.32004  9.64313 33 224495.80575  3.55897 1.749497 35.28 0.5870 34−44.18529  1.00088 35 32.84667  1.10000 1.900433 37.37 0.5772 3616.11826  5.42939 1.632460 63.77 0.5421 37 44.78303  0.12000 38 25.73387 7.06096 1.438750 94.66 0.5340 39 −28.99748  2.00000 1.953748 32.320.5901 40 32.42687 22.34713 41 46.93465  4.05539 1.720467 34.71 0.583542 843.22322  0.00000 43 ∞  2.30000 1.516330 64.14 0.5353 44 ∞ 35.59573

TABLE 16 Example 6 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.81 60.36120.52 Bf 37.11 37.11 37.11 FNo. 3.31 3.31 3.31 2ω(°) 71.30 25.82 13.26DD[14] 1.00 27.09 39.25 DD[16] 1.00 15.00 18.97 DD[23] 46.61 7.17 3.58DD[26] 15.08 14.43 1.89

Example 7

FIG. 8 is a cross-sectional view of a zoom lens of Example 7. The zoomlens of Example 7 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, a fourthlens group G4, an aperture stop St, and a fifth lens group G5. In thesefive lens groups, the distances in the direction of the optical axisbetween groups adjacent to each other change during zooming. The secondlens group G2 has a negative refractive power, the third lens group G3has a positive refractive power, and the fourth lens group G4 has anegative refractive power. The three lens groups including the second tofourth lens groups G2 to G4 are respectively movable lens groups. Thefirst lens group G1 consists of, in order from the object side, a firstlens group front group G1 a consisting of three lenses, a first lensgroup intermediate group G1 b consisting of two lenses, and a first lensgroup rear group G1 c consisting of three lenses. The signs of therefractive powers of three lens groups composing the first lens group G1and the lens groups moving during focusing are the same as that ofExample 1.

Table 17 shows basic lens data of the zoom lens of Example 7, Table 18shows values of specification and variable surface distances, Table 19shows aspheric coefficients, and FIG. 17 shows aberration diagrams in astate where the object at infinity is in focus.

TABLE 17 Example 7 Si Ri Di Ndj vdj θgFj  1 271.02397  2.53000 1.77249949.60 0.5521  2 53.66770 23.14907  3 −176.86065  2.20000 1.695602 59.050.5435  4 430.29449  0.39000  5 90.80833  5.23373 1.892860 20.36 0.6394 6 172.69777  7.52493  7 ∞  5.76344 1.438750 94.66 0.5340  8 −157.36129 0.12000  9 432.45221  4.57630 1.438750 94.66 0.5340  10 −351.9692511.77482  11 105.41212  2.19983 1.846660 23.88 0.6218  12 57.9153516.99595 1.438750 94.66 0.5340  13 −102.71103  0.12000  14 68.91116 6.18166 1.695602 59.05 0.5435  15 251.51097 DD[15] *16 48.87312 1.38000 1.854000 40.38 0.5689  17 23.92316  6.92527  18 −51.61678 1.04910 1.632460 63.77 0.5421  19 37.81667 DD[19]  20 45.09991  5.271631.592701 35.31 0.5934  21 −57.23178  1.05000 1.592824 68.62 0.5441  22−271.05488 DD[22]  23 −42.52742  1.05000 1.632460 63.77 0.5421  2452.07641  3.85263 1.625882 35.70 0.5893  25 −137.87042 DD[25]  26(St) ∞ 1.47098  27 125.78267  3.21681 1.916500 31.60 0.5912  28 −97.17131 0.20021  29 30.88167  7.64434 1.496999 81.54 0.5375  30 −44.27610 1.10005 1.910823 35.25 0.5822  31 79.59338  5.66259  32 38.09474 6.60000 1.749497 35.28 0.5870  33 −103.42350  0.99912  34 128.80899 1.10081 1.900433 37.37 0.5772  35 19.22646 10.52353 1.632460 63.770.5421  36 −168.57645  0.12032  37 35.68369  8.40999 1.438750 94.660.5340  38 −24.74904  1.88371 1.953748 32.32 0.5901  39 26.5834518.87835  40 48.89032  4.75127 1.720467 34.71 0.5835  41 −161.77170 0.00000  42 ∞  2.30000 1.516330 64.14 0.5353  43 ∞ 33.69711

TABLE 18 Example 7 WIDE MIDDLE TELE Zr 1.00 2.90 5.79 f 20.24 58.69117.18 Bf 35.21 35.21 35.21 FNo. 3.32 3.32 3.32 2ω(°) 72.92 26.56 13.64DD[15] 1.00 42.53 58.14 DD[19] 5.98 6.34 5.90 DD[22] 49.90 6.95 6.47DD[25] 14.92 15.98 1.29

TABLE 19 Example 7 Surface Number 16 KA   1.0000000E+00 A3−1.4481371E−20 A4 −2.2097151E−06 A5   1.1906712E−06 A6 −2.1344004E−07 A7  1.2774506E−08 A8   1.1294113E−09 A9 −2.3286340E−10 A10   1.4115083E−11A11   4.6903088E−13 A12 −1.7545649E−13 A13   9.6716937E−15 A14  6.5945061E−16 A15 −7.7270143E−17 A16 −2.4667346E−19 A17  2.3248734E−19 A18 −4.1986679E−21 A19 −2.5896844E−22 A20  7.5912487E−24

Example 8

FIG. 9 is a cross-sectional view of a zoom lens of Example 8. The zoomlens of Example 8 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, a fourthlens group G4, an aperture stop St, and a fifth lens group G5. The firstlens group G1 consists of, in order from the object side, a first lensgroup front group G1 a consisting of three lenses, a first lens groupintermediate group G1 b consisting of two lenses, and a first lens grouprear group G1 c consisting of three lenses. The present example is thesame as Example 5 in terms of the signs of refractive powers of the lensgroups, the lens groups moving during zooming, and the lens groupsmoving during focusing.

Table 20 shows basic lens data of the zoom lens of Example 8, Table 21shows values of specification and variable surface distances, and FIG.18 shows aberration diagrams in a state where the infinite object is infocus.

TABLE 20 Example 8 Si Ri Di Ndj vdj θgFj  1 133.05470  3.50000 1.91082335.25 0.5822  2 54.12002 18.73392  3 −391.71033  3.00000 1.695602 59.050.5435  4 153.38326  0.29128  5 80.45949  5.82006 1.802910 24.97 0.6129 6 157.07544  5.93122  7 781.06706  3.00000 1.805176 25.27 0.6122  8205.52642  9.59605 1.496999 81.54 0.5375  9 −139.61239 15.57700 1097.82514  3.02000 1.655474 40.17 0.5775 11 55.00410 16.96130 1.43875094.66 0.5340 12 −136.52050  0.12063 13 99.75784  6.50803 1.695602 59.050.5435 14 −997.71281 DD[14] 15 98.68615  1.40000 1.910823 35.25 0.582216 33.12062  6.69152 17 −45.09180  1.20000 1.695602 59.05 0.5435 1871.45685 DD[18] 19 85.92877  5.41436 1.698947 31.81 0.5944 20 −50.18700 1.21000 1.695596 56.48 0.5432 21 −96.41737 DD[21] 22 −49.76607  1.210001.695602 59.05 0.5435 23 48.33792  2.79257 1.841398 24.30 0.6159 241002.30801 DD[24] 25(St) ∞  1.46954 26 84.10615  3.51561 1.988478 29.150.6007 27 −120.57733  0.12000 28 35.87832  7.56071 1.496999 81.54 0.537529 −38.14005  1.60026 1.951290 21.53 0.6283 30 95.79248 11.73060 31106.88349  4.42792 1.882244 21.92 0.6244 32 −55.66685  1.95385 3329.67418 10.18976 1.618000 63.33 0.5441 34 −55.23671  1.71475 1.95374832.32 0.5901 35 19.18428  2.24658 36 22.73247  6.92488 1.496999 81.540.5375 37 −21.61774  3.61671 1.900433 37.37 0.5772 38 42.23979 11.8601539 54.60539  5.89772 1.595220 67.73 0.5443 40 −53.31542  0.00000 41 ∞ 2.30000 1.516330 64.14 0.5353 42 ∞ 32.06000

TABLE 21 Example 8 WIDE MIDDLE TELE Zr 1.00 3.10 6.76 f 20.72 64.24139.97 Bf 33.57 33.57 33.57 FNo. 3.31 3.31 3.70 2ω(°) 71.42 24.08 11.30DD[14] 1.00 48.04 66.40 DD[18] 3.20 5.00 2.22 DD[21] 53.14 6.25 5.36DD[24] 18.10 16.15 1.47

Example 9

FIG. 10 is a cross-sectional view of a zoom lens of Example 9. The zoomlens of Example 9 consists of, in order from the object side, a firstlens group G1, a second lens group G2, a third lens group G3, anaperture stop St, and a fourth lens group G4. The first lens group G1consists of one negative lens and five negative lenses in order from theobject side. During focusing, the first to third lenses from the objectside of the first lens group G1 remain stationary with respect to theimage plane Sim, and the fourth to sixth lenses from the object side ofthe first lens group G1 move in the direction of the optical axis. Thesign of the refractive power of each lens group and the lens groupmoving during zooming are the same as those in Example 1.

Table 22 shows basic lens data of the zoom lens of Example 9, Table 23shows values of specification and variable surface distances, and FIG.19 shows aberration diagrams in a state where the infinite object is infocus.

TABLE 22 Example 9 Si Ri Di Ndj vdj θgFj  1 −126.95737  1.85000 1.80610033.27 0.5885  2 149.63908  1.86353  3 162.56196 11.59799 1.433871 95.180.5373  4 −131.43557  0.12017  5 1767.38973  5.79391 1.433871 95.180.5373  6 −161.57632  6.93731  7 143.25520  6.97980 1.433871 95.180.5373  8 −501.53280  0.12020  9 102.71367  7.30164 1.632460 63.770.5421 10 −1279.18292  0.12015 11 52.36368  5.22130 1.695602 59.050.5435 12 90.12596 DD[12] 13 37.28114  0.80009 2.001003 29.13 0.5995 1412.29686  5.14881 15 −79.05024  0.81066 1.695602 59.05 0.5435 1655.48025  1.25321 17 −118.87335  6.29787 1.808095 22.76 0.6307 18−11.60294  0.89994 1.860322 41.97 0.5638 19 139.16815  0.12024 2029.45305  4.40793 1.557208 50.70 0.5593 21 −32.29232  0.13997 22−29.68924  0.91777 1.695602 59.05 0.5435 23 −137.49811 DD[23] 24−26.11338  2.94239 1.731334 29.25 0.6006 25 −16.28232  0.80762 1.69560259.05 0.5435 26 −130.41228 DD[26] 27(St) ∞  1.85032 28 −375.35251 3.66853 1.703851 42.12 0.5727 29 −38.57852  0.17412 30 74.45483 6.67860 1.516330 64.14 0.5353 31 −29.71279  1.20210 1.882997 40.760.5668 32 −69.95930 34.66041 33 234.07781  4.99625 1.517417 52.43 0.556534 −40.81314  0.50000 35 40.64186  5.85957 1.487490 70.24 0.5301 36−46.57752  1.20022 1.806100 33.27 0.5885 37 34.79196  1.36577 3841.96142  8.49290 1.496999 81.54 0.5375 39 −20.65900  1.57625 1.88299740.76 0.5668 40 −136.64621  1.50826 41 99.48573  5.34307 1.595509 39.240.5804 42 −34.92679  0.00000 43 ∞ 33.00000 1.608589 46.44 0.5666 44 ∞13.20000 1.516329 64.05 0.5346 45 ∞ 10.40601

TABLE 23 Example 9 WIDE MIDDLE TELE Zr 1.00 8.00 17.30 f 7.98 63.86138.11 Bf 39.63 39.63 39.63 FNo. 1.86 1.86 2.46 2ω(°) 73.62 9.68 4.52DD[12] 0.76 39.97 45.07 DD[23] 47.38 3.44 7.40 DD[26] 5.62 10.35 1.29

Table 24 shows values corresponding to Conditional Expressions (1) to(7) of the zoom lenses of Examples 1 to 9. The values shown in Table 24are values at the d line.

TABLE 24 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6Example 7 Example 8 Example 9 (1) NF2 + 0.012 × νF2 2.398 2.416 2.3982.416 2.404 2.404 2.398 2.404 2.404 (2) νF2 − νF2 −23.39 −28.25 −32.76−28.25 −16.33 −18.29 −23.39 −23.80 −29.92 (3) NF1 − NF2 0.222 0.2610.270 0.261 0.139 0.187 0.222 0.215 0.305 (4) fF2/fGNF 0.95 0.96 0.950.95 1.05 0.95 1.73 1.84 3.63 (5) NRn + 0.012 × νRn 2.398 2.398 2.3982.398 2.398 2.398 2.398 2.404 2.404 (6) νRn − νRp 28.07 28.07 28.0728.07 28.07 28.07 28.07 34.75 29.80 (7) fRn/fGNR 0.41 0.40 0.47 0.440.41 0.40 0.38 0.41 0.54

As can be seen from the above data, each zoom lens of Examples 1 to 9can be configured to have a small size since the number of lenses of thefirst lens group G1 is restricted to 6 to 8, which is relatively small.Therefore, the zoom ratio is in a range of 5.79 to 17.3 such that thehigh zoom ratio is ensured, and various aberrations including chromaticaberration are satisfactorily corrected, whereby high opticalperformance is realized.

Next, an imaging apparatus according to an embodiment of the presentinvention will be described. FIG. 20 is a schematic configurationdiagram of an imaging apparatus 10 using the zoom lens 1 according tothe above-mentioned embodiment of the present invention as an example ofan imaging apparatus of an embodiment of the present invention. Examplesof the imaging apparatus 10 include a movie imaging camera, a broadcastcamera, a digital camera, a video camera, a surveillance camera, and thelike.

The imaging apparatus 10 comprises a zoom lens 1, a filter 2 which isdisposed on the image side of the zoom lens 1, and an imaging element 3which is disposed on the image side of the filter 2. FIG. 20schematically shows the first lens group front group G1 a, the firstlens group intermediate group G1 b, the first lens group rear group G1c, and the second to fourth lens groups G2 to G4 included in the zoomlens 1. The imaging element 3 captures an optical image, which is formedthrough the zoom lens 1, and converts the image into an electricalsignal. For example, charge coupled device (CCD), complementary metaloxide semiconductor (CMOS), or the like may be used. The imaging element3 is disposed such that the imaging surface thereof is coplanar with theimage plane of the zoom lens 1.

The imaging apparatus 10 also comprises a signal processing section 5which performs calculation processing on an output signal from theimaging element 3, a display section 6 which displays an image formed bythe signal processing section 5, a zoom control section 7 which controlszooming of the zoom lens 1, and a focus control section 8 which controlsfocusing of the zoom lens 1. It should be noted that FIG. 20 shows onlyone imaging element 3, but the imaging apparatus of the presentinvention is not limited to this, and may be a so-called three-plateimaging apparatus having three imaging elements.

The present invention has been hitherto described through embodimentsand examples, but the present invention is not limited to theabove-mentioned embodiments and examples, and may be modified intovarious forms. For example, values such as the radius of curvature, thesurface distance, the refractive index, the Abbe number, and theaspheric coefficient of each lens are not limited to the values shown inthe numerical examples, and different values may be used therefor.

EXPLANATION OF REFERENCES

-   1: zoom lens-   2: filter-   3: imaging element-   5: signal processing section-   6: display section-   7: zoom control section-   8: focus control section-   10: imaging apparatus-   G1: first lens group-   G1 a: first lens group front group-   G1 b: first lens group intermediate group-   G1 c: first lens group rear group-   G2: second lens group-   G3: third lens group-   G4: fourth lens group-   G5: fifth lens group-   Ge: final lens group-   GNF: front side negative lens group-   GNR: rear side negative lens group-   L11 to L18, L21 to L24, L31 to L32, L41 to L49: lens-   PP: optical member-   Sim: image plane-   St: aperture stop-   ma, ta, wa: on-axis rays-   mb, tb, wb: rays with maximum angle of view-   Z: optical axis

What is claimed is:
 1. A zoom lens comprising, in order from an objectside: a first lens group that has a positive refractive power andremains stationary with respect to an image plane during zooming; aplurality of movable lens groups that move by changing distances betweengroups adjacent to each other in a direction of an optical axis duringzooming; and a final lens group that has a positive refractive power andremains stationary with respect to the image plane during zooming,wherein in the plurality of movable lens groups, at least two movablelens group all have a negative refractive power, wherein in a case wherethe movable lens group which is closest to the object side and has anegative refractive power is set as a front side negative lens group,the front side negative lens group has two or more negative lenses,wherein in a case where the movable lens group which is closest to animage side and has a negative refractive power is set as a rear sidenegative lens group, the rear side negative lens group includes anegative lens and a positive lens, and wherein all ConditionalExpressions (1) to (3), (5) and (6) are satisfied,2.395<NF2+0.012×vF2<2.495   (1),−35<vF1−vF2<−16   (2),and0.12<NF1−NF2<0.34   (3),2.395<NRn+0.012×vRn<2.495   (5),and25<vRn−vRp<35   (6), where NF2 is a refractive index of a secondnegative lens from the object side in the front side negative lens groupat the d line, vF2 is an Abbe number of the second negative lens fromthe object side in the front side negative lens group at the d line, vF1is an Abbe number of a negative lens closest to the object side in thefront side negative lens group at the d line, NF1 is a refractive indexof the negative lens closest to the object side in the front sidenegative lens group at the d line, NRn is a refractive index of thenegative lens of the rear side negative lens group at the d line, vRn isan Abbe number of the negative lens of the rear side negative lens groupat the d line, and vRp is an Abbe number of the positive lens of therear side negative lens group at the d line.
 2. The zoom lens accordingto claim 1, wherein Conditional Expression (4) is satisfied,0.93<fF2/fGNF<1.1   (4), where fF2 is a focal length of the secondnegative lens from the object side in the front side negative lensgroup, and fGNF is a focal length of the front side negative lens group.3. The zoom lens according to claim 1, wherein Conditional Expression(7) is satisfied,0.35<fRn/fGNR<0.51   (7), where fRn is a focal length of the negativelens of the rear side negative lens group, and fGNR is a focal length ofthe rear side negative lens group.
 4. The zoom lens according to claim2, wherein Conditional Expression (7) is satisfied,0.35<fRn/fGNR<0.51   (7), where fRn is a focal length of the negativelens of the rear side negative lens group, and fGNR is a focal length ofthe rear side negative lens group.
 5. The zoom lens according to claim1, wherein Conditional Expression (1-1) is satisfied.2.395<NF2+0.012×vF2<2.455   (1-1)
 6. The zoom lens according to claim 2,wherein Conditional Expression (1-1) is satisfied.2.395<NF2+0.012×vF2<2.455   (1-1)
 7. The zoom lens according to claim 3,wherein Conditional Expression (1-1) is satisfied.2.395<NF2+0.012×vF2<2.455   (1-1)
 8. The zoom lens according to claim 4,wherein Conditional Expression (1-1) is satisfied.2.395<NF2+0.012×vF2<2.455   (1-1)
 9. The zoom lens according to claim 1,wherein Conditional Expression (2-1) is satisfied.−33<vF1−vF2<−18   (2-1)
 10. The zoom lens according to claim 2, whereinConditional Expression (2-1) is satisfied.−33<vF1−vF2<−18   (2-1)
 11. The zoom lens according to claim 3, whereinConditional Expression (2-1) is satisfied.−33<vF1−vF2<−18   (2-1)
 12. The zoom lens according to claim 1, whereinConditional Expression (3-1) is satisfied.0.13<NF1−NF2<0.31   (3-1)
 13. The zoom lens according to claim 1,wherein Conditional Expression (4-1) is satisfied,0.94<fF2/fGNF<1.05   (4-1), where fF2 is a focal length of the secondnegative lens from the object side in the front side negative lensgroup, and fGNF is a focal length of the front side negative lens group.14. The zoom lens according to claim 1, wherein Conditional Expression(5-1) is satisfied.2.395<NRn+0.012×vRn2<2.455   (5-1)
 15. The zoom lens according to claim1, wherein Conditional Expression (6-1) is satisfied.27<vRn−vRp<30   (6-1)
 16. The zoom lens according to claim 1, whereinConditional Expression (7-1) is satisfied,0.37<fRn/fGNR<0.48   (7-1), where fRn is a focal length of the negativelens of the rear side negative lens group, and fGNR is a focal length ofthe rear side negative lens group.
 17. The zoom lens according to claim1, wherein the plurality of movable lens groups includes a lens grouphaving a negative refractive power and a lens group having a negativerefractive power.
 18. The zoom lens according to claim 1, wherein theplurality of movable lens groups includes, in order from the objectside, a lens group having a positive refractive power, a lens grouphaving a negative refractive power, and a lens group having a negativerefractive power.
 19. The zoom lens according to claim 1, wherein theplurality of movable lens groups includes, in order from the objectside, a lens group having a negative refractive power, a lens grouphaving a positive refractive power, and a lens group having a negativerefractive power.
 20. An imaging apparatus comprising the zoom lensaccording to claim 1.